package chapter2;

import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

/**
 * Basic symmetric encryption example with padding and CBC using DES
 */
public class SimpleCBCExample {
	public static void main(String[] args) throws Exception {
		Security.addProvider(new BouncyCastleProvider());
		byte[] input = "dfadfadfadfaffdafdafasdfadfadfadfqertqerqdfadfa".getBytes();
		byte[] input2 = "sbdfasdfadfadfafdadfadfasdfadfadf".getBytes();
		byte[] keyBytes = new byte[] { 0x01, 0x23, 0x45, 0x67, (byte) 0x89, (byte) 0xab, (byte) 0xcd, (byte) 0xef };
		byte[] ivBytes = new byte[] { 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00 };

		SecretKeySpec key = new SecretKeySpec(keyBytes, "DES");
		IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS7Padding", "BC");

		System.out.println("input : " + new String(input));

		// encryption pass
		
		cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);

		byte[] cipherText = new byte[cipher.getOutputSize(input.length + input2.length + input2.length)];

		int ctLength = cipher.update(input, 0, input.length, cipherText, 0);

		System.out.println("cipher: " + Utils.toHex(cipherText, ctLength) + " bytes: " + ctLength);

		ctLength += cipher.update(input2, 0, input2.length, cipherText, ctLength);

		System.out.println("cipher: " + Utils.toHex(cipherText, ctLength) + " bytes: " + ctLength);
		ctLength += cipher.update(input2, 0, input2.length, cipherText, ctLength);

		System.out.println("cipher: " + Utils.toHex(cipherText, ctLength) + " bytes: " + ctLength);
		
		ctLength += cipher.doFinal(cipherText, ctLength);

		System.out.println("cipher: " + Utils.toHex(cipherText, ctLength) + " bytes: " + ctLength);

		// decryption pass

		cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);

		byte[] doFinal = cipher.doFinal(cipherText);

		System.out.println(new String(doFinal));
		// byte[] plainText = new byte[cipher.getOutputSize(ctLength)];
		// System.out.println(plainText.length);
		//
		// int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);
		//
		// System.out.println(ptLength);
		// System.out.println("plain : " + new String(plainText) + " bytes: " +
		// ptLength);
		//
		// System.out.println(cipher.doFinal(plainText, ptLength));
		//
		// System.out.println("plain : " + new String(plainText) + " bytes: " +
		// ptLength);
	}
}
